Stabilized hypochlorous acid solution and use thereof

ABSTRACT

Disclosed is an antimicrobial solution comprising, consisting essentially of or consisting of (a) hypochlorous acid, (b) a divalent cation, (c) phosphate anion, and (d) water, as well as a process for its production. Also disclosed is a method of treating or preventing infection associated with abdominal surgery on a mammal, comprising use of the antimicrobial solution.

CROSS-REFERENCE TO RELATED APPLICATIONS

This patent application is the U.S. national phase of InternationalApplication No. PCT/US2014/039202, filed on May 22, 2014, which claimsthe benefit of U.S. Provisional Application No. 61/826,382, filed May22, 2013, the disclosures of which are incorporated herein by referencein their entireties for all purposes.

BACKGROUND OF THE INVENTION

In human patients undergoing abdominal surgery, Gram-positive bacteriaand/or Gram-negative bacteria, which are normally present in theintestine, can cross the intestinal wall and reach the circulation.During surgery and/or preceding surgery, conditions such as fasting andischaemia can be present which facilitate the bacterial translocation.In addition, the surgical procedure itself may result in a disruptedintestinal barrier, particularly during abdominal surgery. Thistranslocation results in short and midterm complications includingsepsis, bacteraemia, and endotoxaemia. Peritonitis, which is aninflammation of the peritoneum, also can result as a consequence ofinfection by microorganisms residing within the intestines which can bereleased during a surgical procedure.

Sepsis (or septic shock or septicemia) is a disorder which occurs when arelatively large amount of micro-organisms, or fragments thereof, enterthe body. It is characterized as a systemic disease associated with thepresence and persistence of pathogenic micro-organisms or their toxinsin the blood. The presence of endotoxins, such as lipopolysaccharide(LPS), lipoteichoic acid (LTA) and/or peptidoglycan (PG), in the bloodgives rise to a condition known as endotoxaemia or endotoxic shock. Whenthe micro-organisms which have entered the blood are viable, thiscondition is also referred to as bacteraemia.

The intestine, especially the colon and the lower part of the smallintestine, is a reservoir of LPS and Gram-negative bacteria, such as thecommon inhabitant Escherichia coli, but also of LTA, PG andGram-positive bacteria. The presence of Gram-negative and/orgram-positive bacteria and/or LPS and/or LTA and/or PG in the gut doesnot create any issues for a healthy individual. However, upon increaseof the intestinal permeability or decrease of the intestinal integrityduring or after surgery, this can become a problem. Sepsis, bacteraemiaand/or endotoxaemia lead to a prolonged hospital stay and thus increasedcosts and increased morbidity. It can also lead to multiple organfailure or even death. It is, therefore, of great importance to find amethod to treat, and especially to prevent bacterial translocation andresulting infection during or shortly after surgery.

BRIEF SUMMARY OF THE INVENTION

The invention provides an antimicrobial solution comprising (a)hypochlorous acid, (b) a divalent cation, (c) phosphate anion, and (d)water. The invention also provides a process for the production of anantimicrobial solution comprising the steps of (i) providing a mixturecomprising (a) a divalent cation, (b) a phosphate anion, (c) apH-adjusting agent, and (d) water, and (ii) adding chlorine gas to themixture. The invention additionally provides a method of treating orpreventing infection associated with abdominal surgery on a mammal,comprising administering to the mammal an effective amount of anantimicrobial solution comprising (a) hypochlorous acid, (b) a divalentcation, (c) phosphate anion, and (d) water.

DETAILED DESCRIPTION OF THE INVENTION

The invention provides an antimicrobial solution comprising, consistingessentially of, or consisting of (a) hypochlorous acid, (b) a divalentcation, (c) phosphate anion, and (d) water.

The solution contains hypochlorous acid. The hypochlorous acid can beprepared using any suitable process. In an embodiment, the hypochlorousacid can be prepared by adding chlorine to water. In other embodiments,the hypochlorous acid can be prepared via electrochemical generationfrom an aqueous sodium chloride solution. In these embodiments, thehypochlorous acid can be prepared in a batch mode using a single chamberelectrolysis cell, or the hypochlorous acid can be prepared in acontinuous mode using a two- or three-chambered electrolysis cell.Examples of suitable three-chambered electrolysis cells are disclosed inU.S. Patent Application Publications 2005/0139808 A1 and 2005/0142157A1, the disclosure of which are incorporated totally herein byreference.

The solution can contain any suitable amount of hypochlorous acid. Thesolution can contain about 10 mg/L or more, about 20 mg/L or more, about30 mg/L or more, about 40 mg/L or more, about 50 mg/L or more, about 60mg/L or more, about 70 mg/L or more, about 80 mg/L or more, about 90mg/L or more, or about 100 mg/L or more of hypochlorous acid.Alternatively, or in addition, the solution can contain about 500 mg/Lor less, about 450 mg/L or less, about 400 mg/L or less, about 350 mg/Lor less, about 300 mg/L or less, about 250 mg/L or less, about 200 mg/Lor less, or about 150 mg/L or less of hypochlorous acid. Thus, thesolution can contain hypochlorous acid in an amount bounded by any twoof the aforementioned endpoints. For example, the solution can containabout 10 mg/L to about 500 mg/L, about 10 mg/L to about 400 mg/L, about10 mg/L to about 300 mg/L, about 10 mg/L to about 200 mg/L, about 20mg/L to about 200 mg/L, about 30 mg/L to about 200 mg/L, about 40 mg/Lto about 200 mg/L, about 50 mg/L to about 200 mg/L, about 50 mg/L toabout 150 mg/L, or about 100 mg/L to about 150 mg/L of hypochlorousacid.

The solution contains a divalent cation. In certain embodiments, thedivalent cation is magnesium, calcium, or a combination thereof. Incertain embodiments, the divalent cation is magnesium. In certainembodiments, the divalent cation is calcium. In certain preferredembodiments, the divalent cation is magnesium.

The divalent cation can be provided as a component of any suitablecompound. In certain embodiments, the divalent cation is a component ofa salt. The salt can be any suitable salt. For example, the salt maycomprise the divalent cation as the cationic component thereof and ananionic component selected from sulfate, nitrate, hydroxide, carbonate,hydrogencarbonate, halide (e.g., chloride, bromide, iodide, orfluoride), sulfonate, alkylsulfonate, and the like. In certain preferredembodiments, the salt comprises sulfate as the anionic component. Incertain more preferred embodiments, the salt is magnesium sulfate orcalcium sulfate, or a combination thereof.

The solution can contain any suitable amount of the divalent cation. Thesolution can contain about 20 mg/L or more, about 30 mg/L or more, about40 mg/L or more, about 50 mg/L or more, about 60 mg/L or more, about 70mg/L or more, about 80 mg/L or more, about 90 mg/L or more, or about 100mg/L or more of the divalent cation. Alternatively, or in addition, thesolution can contain about 250 mg/L or less, about 225 mg/L or less,about 200 mg/L or less, about 175 mg/L or less, about 150 mg/L or less,or about 250 mg/L or less, about 200 mg/L or less, or about 150 mg/L orless of the divalent cation.

Accordingly, the solution can contain the divalent cation in an amountbounded by any two of the aforementioned endpoints. For example, thesolution can contain about 20 mg/L to about 250 mg/L, about 20 mg/L toabout 225 mg/L, about 20 mg/L to about 200 mg/L, about 20 mg/L to about175 mg/L, about 20 mg/L to about 150 mg/L, about 30 mg/L to about 200mg/L, about 40 mg/L to about 200 mg/L, about 50 mg/L to about 200 mg/L,about 50 mg/L to about 150 mg/L, about 75 mg/L to about 125 mg/L, orabout 100 mg/L to about 150 mg/L of the divalent cation.

The solution contains phosphate anion. The phosphate anion can beprovided using any suitable source of phosphate anion. As is well knownin the art, phosphate anions are derived from phosphorous acid and canbe phosphate anion (PO₄ ³⁻), hydrogenphosphate anion (HPO₄ ²⁻), ordihydrogenphosphate anion (H₂PO⁴⁻). The phosphate anion can be providedas a component of any suitable compound. In certain embodiments, thephosphate anion is a component of a salt. The salt can be any suitablesalt. For example, the salt may comprise the phosphate anion as theanionic component thereof and a cationic component selected from alkalimetal (e.g., Li, Na, K), ammonium, and the like. In certain preferredembodiments, the salt comprises sodium as the cationic component. Incertain more preferred embodiments, the salt is sodium dihydrogenphosphate. The salt can be anhydrous or can be a hydrate (e.g., sodiumdihydrogen phosphate monohydrate).

The solution can contain any suitable amount of the phosphate anion. Inthis regard, the amount of phosphate anion is calculated on the basis ofphosphate anion formulated as PO₄ ³⁻. Thus, for example, the amount ofthe source of phosphate anion used in the antimicrobial solution iscalculated to provide the amount of phosphate anion formulated as PO₄ ³⁻as recited herein. The solution can contain about 200 mg/L or more,about 220 mg/L or more, about 240 mg/L or more, about 260 mg/L or more,about 280 mg/L or more, about 300 mg/L or more, about 320 mg/L or more,about 340 mg/L or more, about 360 mg/L or more, about 380 mg/L or more,or about 400 mg/L or more of the phosphate anion. Alternatively, or inaddition, the solution can contain about 1000 mg/L or less, about 900mg/L or less, about 800 mg/L or less, about 700 mg/L or less, about 600mg/L or less, about 580 mg/L or less, about 560 mg/L or less, about 540mg/L or less, about 520 mg/L or less, or about 500 mg/L or less, about480 mg/L or less, about 460 mg/L or less, about 440 mg/L or less, about420 mg/L or less, or about 400 mg/L or less of the phosphate anion.

Accordingly, the solution can contain the phosphate anion in an amountbounded by any two of the aforementioned endpoints. For example, thesolution can contain about 200 mg/L to about 1000 mg/L, about 200 mg/Lto about 900 mg/L, about 200 mg/L to about 800 mg/L, about 200 mg/L toabout 700 mg/L, about 200 mg/L to about 600 mg/L, about 200 mg/L toabout 580 mg/L, about 200 mg/L to about 560 mg/L, about 200 mg/L toabout 540 mg/L, about 200 mg/L to about 520 mg/L, about 200 mg/L toabout 500 mg/L, or about 300 mg/L to about 500 mg/L of the phosphateanion.

The solution optionally further comprises chloride ion. The chloride ioncan be provided by any suitable source of chloride ion. For example, thechloride ion can be provided in the form of an added salt. In certainembodiments, the hypochlorous acid is generated in situ by the additionof chlorine gas to water. The chlorine gas reacts with water to producehypochlorous acid and one equivalent of chloride ion in the form ofhydrochloric acid: Cl₂+H2O→HOCl+HCl.

The solution can contain any suitable amount of chloride ion. Thesolution can contain about 10 mg/L or more, about 20 mg/L or more, about30 mg/L or more, about 40 mg/L or more, about 50 mg/L or more, about 60mg/L or more, about 70 mg/L or more, about 80 mg/L or more, about 90mg/L or more, or about 100 mg/L or more of chloride ion. Alternatively,or in addition, the solution can contain about 300 mg/L or less, about280 mg/L or less, about 260 mg/L or less, about 240 mg/L or less, about220 mg/L or less, or about 200 mg/L or less of chloride ion. Thus, thesolution can contain chloride ion in an amount bounded by any two of theaforementioned endpoints. For example, the solution can contain about 10mg/L to about 300 mg/L, about 20 mg/L to about 280 mg/L, about 30 mg/Lto about 260 mg/L, about 40 mg/L to about 240 mg/L, about 50 mg/L toabout 220 mg/L, or about 60 mg/L to about 200 mg/L of chloride ion.

The solution has a pH of about 3 or more, about 3.5 or more, or about4.5 or more. Alternatively, or in addition, the solution has a pH ofabout 7 or less, about 6.5 or less, about 6 or less, or about 5.5 orless. Thus, the solution can have a pH bounded by any two of theaforementioned endpoints. For example, the solution can have a pH ofabout 3 to about 7, about 3 to about 6.5, about 3 to about 6, about 3 toabout 5.5, about 3.5 to about 7, about 3.5 to about 6.5, about 3.5 toabout 6, about 3.5 to about 5.5, about 4 to about 7, about 4 to about6.5, about 4 to about 6, about 4 to about 5.5, about 4.5 to about 7,about 4.5 to about 6.5, about 4.5 to about 6, or about 4.5 to about 5.5.

The solution optionally comprises a compound capable of adjusting and/orbuffering the pH. The compound capable of adjusting and/or buffering thepH can be selected from the group consisting of alkali metal salts,carboxylic acids, alkali metal hydroxides, alkali metal carbonates,alkali metal bicarbonates, borates, and mixtures thereof. In certainpreferred embodiments, the compound capable of adjusting and/orbuffering the pH is an alkali metal hydroxide, for example, sodiumhydroxide.

In certain preferred embodiments, the solution comprises (a) about 10mg/L to about 500 mg/L of hypochlorous acid, (b) magnesium sulfate in anamount sufficient to provide about about 20 mg/L to about 250 mg/L ofmagnesium, (c) sodium dihydrogen phosphate is present in an amountsufficient to provide about 200 mg/L to about 1000 mg/L of phosphateanion formulated as PO₄ ²⁻, (d) about 20 mg/L to about 100 mg/L ofchloride ion, and (e) water, wherein the solution has a pH of about 3 toabout 7.

It is believed that the phosphate anion can provide buffering of the pHof the antimicrobial solution to a preferred pH range. However, asignificant amount of phosphate anion is required to exhibit bufferingactivity at this pH range. It is known that phosphate anion increasesthe degradation rate of hypochlorous acid. It has been unexpectedlyfound that the combination of divalent cation and phosphate anion allowsfor a reduction in the amount of phosphate anion required to provide abuffering action and further exhibits a significantly reduced rate ofhypochlorous acid degradation.

The antimicrobial solution of the present invention is generally stablefor at least twenty-hours, and typically at least two days. Moretypically, the solution is stable for at least one week (e.g., one week,two weeks, three weeks, four weeks, etc.), and preferably at least twomonths. More preferably, the solution is stable for at least six monthsafter its preparation. Even more preferably, the solution is stable forat least one year, and most preferably for at least three years.

As used herein, the term stable generally refers to the ability of theantimicrobial water solution to remain suitable for its intended use,for example, in surgical applications, decontamination, disinfection,sterilization, anti-microbial cleansing, and wound cleansing, for aspecified period of time after its preparation under normal storageconditions (i.e., room temperature). In this regard, the antimicrobialsolution of the present invention is also stable when stored underaccelerated conditions, typically about 30° C. to about 60° C., for atleast 90 days, and preferably 180 days.

The concentrations of ionic and other species present in solution aregenerally maintained during the shelf-life of the antimicrobialsolution. Typically, the concentration of hypochlorous acid ismaintained at about 70% or greater from its initial concentration for atleast two months after preparation of the antimicrobial solution.Preferably, this concentration is maintained at about 80% or greater ofits initial concentration for at least two months after preparation ofthe solution. More preferably, this concentration is at about 90% orgreater of ita initial concentration for at least two months afterpreparation of the solution, and most preferably, about 95% or greater.

The stability of the antimicrobial solution of the present invention maybe determined based on the reduction in the amount of livemicroorganisms present in a sample following exposure to the solution.The measurement of the reduction of organism concentration may becarried out using any suitable organism including bacteria, fungi,yeasts, or viruses, as described herein. The low pH antimicrobialsolution is useful as both a low-level disinfectant capable of a fourlog (10⁴) reduction in the concentration of live microorganisms and ahigh-level disinfectant capable of a six log (10⁶) reduction inconcentration of live microorganisms.

In one embodiment of the present invention, the antimicrobial solutionis capable of yielding at least a four log (10⁴) reduction in totalorganism concentration following exposure for one minute, when measuredat least two months after preparation of the solution. Preferably, thesolution is capable of such a reduction of organism concentration whenmeasured at least six months after preparation of the solution. Morepreferably, the solution is capable of such a reduction of organismconcentration when measured at least one year after preparation, andmost preferably when measured at least three years after preparation.

In another embodiment the present invention, the antimicrobial solutionis capable of yielding at least a six log (10⁶) reduction in totalorganism concentration within one minute of exposure, when measured atleast two months after preparation of the solution. Preferably, thesolution is capable of achieving this reduction when measured at leastsix months after preparation, and more preferably at least one yearafter preparation. Preferably, the solution is capable of at least aseven log (10⁷) reduction in the concentration of live microorganismswithin one minute of exposure, when measured at least two months afterpreparation.

The invention also provides a pharmaceutical composition comprising theantimicrobial solution and a pharmaceutically acceptable carrier. Theantimicrobial solution can be administered alone or in combination withone or more pharmaceutically acceptable carriers, e.g., vehicles,adjuvants, excipients, diluents, combinations thereof, and the like,which are preferably compatible with one or more of the species thatexist in the antimicrobial solution. One skilled in the art can easilydetermine the appropriate formulation and method for administering theantimicrobial solution used in accordance with the present invention.For instance, the use of a gel based formulation containing theantimicrobial solution can be used to maintain hydration of theabdominal cavity while providing a barrier against microorganisms.Suitable gel formulations are described, e.g., in U.S. PatentApplication Publication No. US 2005/0142157 A1 (hereby incorporated byreference). Any necessary adjustments in dose can be readily made by askilled practitioner to address the nature and/or severity of thecondition being treated in view of one or more clinically relevantfactors, such as, e.g., side effects, changes in the patient's overallcondition, and the like.

For example, the antimicrobial solution can be formulated by combiningor diluting the HOCl water solution with about 25% (wt./wt. orvol./vol.) of a suitable carrier, about 50% (wt./wt. or vol./vol.) of asuitable carrier, about 75% (wt./wt. or vol./vol.) of a suitablecarrier, about 90% (wt./wt. or vol./vol.) of a suitable carrier, about95% (wt./wt. or vol./vol.) of a suitable carrier, or even with about 99%(wt./wt. or vol./vol.) or more of a suitable carrier. Suitable carrierscan include, e.g., water (e.g., distilled water, sterile water, e.g.,sterile water for injection, sterile saline and the like). Suitablecarriers also can include one or more carriers described in U.S. patentapplication Ser. No. 10/916,278 (hereby incorporated by reference).Exemplary formulations can include, e.g., solutions in which theantimicrobial solution is diluted with sterile water or sterile saline,wherein the antimicrobial solution is diluted by about 25% (vol./vol.),by about 50% (vol./vol.), by about 75% (vol./vol.), by about 90%(vol./vol.), by about 95% (vol./vol.), or by 99% (vol./vol.) or more,depending on the therapeutic application and/or any othertherapeutically relevant factors.

The antimicrobial solution and pharmaceutical compositions comprisingthe same can be sterilized prior to or after packaging. For example, thesterilization can be carried out by autoclaving at an elevatedtemperature for a period of time (e.g., at 121° C. for 40 min).

The invention also provides a process for the production of anantimicrobial solution comprising the steps of (i) providing a mixturecomprising (a) a divalent cation, (b) a phosphate anion, (c) apH-adjusting agent, and (d) water, and (ii) adding chlorine gas to themixture. The components can be provided in any order. For example thedivalent cation, phosphate anion, pH-adjusting agent, and water can becombined in any order. The chlorine gas can be added to the mixturebefore, during, or after the addition of any other of the components.Optional chloride ion can be added at any stage of the process. Asdiscussed herein, chlorine gas reacts with water to produce hypochlorousacid and hydrochloric acid. Hydrochloric acid reacts with thepH-adjusting agent to produce water and chloride ions. In an embodiment,the chlorine gas is bubbled into the solution, either prior to additionof the additional components, after addition of one or more of theadditional components, or after addition of all of the additionalcomponents.

The process can be carried out in a batch mode or in a continuous mode.For example, the process can be carried out in a flow apparatus in whichthe components of the solution can be added in the form of solutions,while chlorine gas is bubbled into the flow stream. Alternatively, thechlorine gas can be added to water, and the resulting solutionintroduced into the flow apparatus at any suitable point.

In another embodiment, the invention provides a process for theproduction of an antimicrobial solution comprising the steps of (i)providing a mixture comprising hypochlorous acid and water, and (ii)adding (a) a divalent cation, (b) a phosphate anion, and (c) apH-adjusting agent to the mixture.

The hypochlorous acid can be prepared using any suitable process asdiscussed herein in connection with the inventive antimicrobialsolution. In an embodiment, the hypochlorous acid can be prepared byadding chlorine to water. In other embodiments, the hypochlorous acidcan be prepared via electrochemical generation from an aqueous sodiumchloride solution using a single chamber cell or using two- andthree-chambered cells. In some embodiments, arrangements comprisingmultiple cells can be utilized to provide the hypochlorous acid.

The other components, i.e., the divalent cation, the phosphate anion,and the pH-adjusting agent, and compounds comprising the aforesaidcomponents, can be provided in the form of solids or in the form ofsolutions comprising the aforesaid components. The components may bemixed using any suitable method capable of incorporating the componentsinto the solution. For example, a mixture comprising the components maybe stirred in a vessel for a time sufficient to incorporate thecomponents into the solution.

Following its preparation, the antimicrobial solution of the presentinvention may be transferred to a sealed container for distribution andsale to end users such as, for example, health care facilities includinghospitals, nursing homes, doctor offices, outpatient surgical centers,dental offices, and the like. Any suitable sealed container may be usedthat maintains the sterility and stability of the antimicrobial solutionheld by the container. The container may be constructed of any materialthat is compatible with the solution and should be generallynon-reactive so that the ions present in the solution do not react withthe container to any appreciable extent.

Preferably, the container is constructed of plastic or glass. Theplastic may be rigid so that the container is capable of being stored ona shelf. Alternatively, plastic may be flexible, such as a flexible bag.

Suitable plastics include polypropylene, polyethylene terephthalate(PET), polyolefin, cycloolefin, polycarbonate, ABS resin, polyethylene,polyvinyl chloride, and mixtures thereof. Preferably, the containercomprises polyethylene selected from the group consisting ofhigh-density polyethylene (HDPE), low-density polyethylene (LDPE), andlinear low-density polyethylene (LLDPE). Most preferably, the containeris high density polyethylene or polyethylene terephthalate.

The container has an opening to permit dispensing of the low pHantimicrobial solution. The container opening may be sealed in anysuitable manner. For example, the container may be sealed with atwist-off cap or stopper. Optionally, the opening may be further sealedwith a foil layer.

The headspace gas of the sealed container may be air or other suitablegas that does not react with the low pH antimicrobial solution. Suitableheadspace gases included nitrogen, oxygen, and mixtures thereof.

The antimicrobial solution can be provided in the form of a kitcomprising the antimicrobial solution, by itself or in the form of acomposition comprising the same, and further including instructions forthe use thereof.

The invention also provides a method of treating or preventing infectionassociated with abdominal surgery on a mammal, comprising administeringto the mammal an effective amount of the antimicrobial solution or thepharmaceutical composition as described herein. In certain embodiments,the surgery is inguinal hernia surgery, exploratory laparotomy,appendectomy, or laparoscopy.

The term abdominal surgery broadly covers surgical procedures thatinvolve opening the abdomen. The most common abdominal surgeries includeinguinal hernia surgery, exploratory laparotomy, appendectomy, andlaparoscopy. Inguinal hernia surgery refers to the repair of an inguinalhernia. Exploratory laparotomy refers to the opening of the abdominalcavity for direct examination of the contents thereof, for example, tolocate a source of bleeding or the location of a trauma. The proceduremay or may not be followed by repair or removal of the source of theprimary problem. Appendectomy refers to surgical opening of theabdominal cavity and removal of the appendix. Laparoscopy refers to aminimally invasive approach to abdominal surgery wherein tubes and otherinstruments are inserted into the abdominal cavity via small incisions.The most common laparoscopic procedure is cholecystectomy (gallbladderremoval), but many other procedures are also performed usinglaparascopic techniques, for example, various gynecological procedures.

Advantageously, use of the inventive antimicrobial solution duringabdominal surgery prevents or treats infection associated with abdominalsurgery.

In accordance with certain embodiments, a therapeutically effectiveamount of the antimicrobial solution can be administered by deliveringthe antimicrobial solution to the abdominal cavity using any suitabledelivery method, to treat or prevent infections. A therapeuticallyeffective amount of the antimicrobial can be delivered to the patient'sabdominal cavity intra-operatively, laproscopically, ortransabdominally. The antimicrobial solution can be delivered, e.g., toperitoneal tissue susceptible for developing an infection (e.g., as aresult of surgery, laparoscopic-diagnostic procedures, injury,infection, disease, allergic reaction, contact with one or more chemicalirritants, or proximity to impaired, damaged and/or infected tissue, andthe like).

Abdominal lavage, e.g., repeated flushings of the abdominal cavity, withthe antimicrobial solution can be used to perform the method of thepresent invention. The antimicrobial solution can be retained in theabdominal cavity for any suitable length of time, e.g., a period of timeeffective to provide a therapeutic response, which can be seconds,minutes, hours, or days. In one embodiment, the present inventionprovides a method of treating or preventing infection, which methodincludes gaining access to the abdominal space, e.g., surgically ortransabdominally; delivering to the patient's abdominal cavity of atherapeutically effective amount of the antimicrobial solution, e.g.,about 1-10 liters, allowing the water to remain in the abdominal cavityfor a period of time sufficient to effectuate a therapeutic response,e.g., seconds, minutes, or hours; optionally removing the antimicrobialsolution from the abdominal cavity; optionally, removing theantimicrobial solution from the abdominal cavity; optionally, deliveringsaline or other physiologic solution prior or after delivering theantimicrobial solution; and optionally, repeating the abdominal lavagefor as many times as necessary.

A therapeutically effective amount of the antimicrobial solution can bedelivered to the abdominal cavity, e.g., by gravity (e.g., by pouring ordispensing the antimicrobial solution from a container or device) or bydelivering the antimicrobial solution under pressure (e.g., byspraying). One or more flushings of the abdominal cavity can beperformed, i.e., the abdominal cavity can be “lavaged.” Theantimicrobial solution can be retained in the abdominal cavity for anysuitable length of time, e.g., a period of time effective to provide atherapeutic response, e.g., seconds, minutes, hours, or days, andoptionally removed using any suitable method. Suitable methods ofremoval can include, e.g., allowing the antimicrobial solution to benaturally absorbed into one or more surrounding tissues, blotting withone or more absorbent materials (e.g., gauze, sponge, towel, or mesh),removal by suction, and the like, and combinations thereof.

The inventive method can treat or prevent infection caused by anysuitable microorganism. In certain embodiments, the inventive methodtreats or prevents infection caused by an organism selected frommethicilln-resistant S. aureus, E. coli, P. aeruginosa,Vancomycin-resistant Enterococcus, P. mirabilis, S. marcescens, and C.albicans.

A surgeon can assess the effectiveness of the treatment using methodscommonly known in the art. For example, a surgeon or other physician canperform examination of fluids or tissues obtained from the abdominalcavity for the presence of absence of infections microorganisms. Inother embodiments, the surgeon or physician can assess the mammal forsecondary indications of infection such as, increased body temperature,increase in white blood cell count, and the like.

The therapeutically effective amount administered to the patient, e.g.,a mammal, particularly a human, in the context of the present inventionshould be sufficient to affect a therapeutic or prophylactic response inthe patient over a reasonable time frame. The dose can be readilydetermined using methods that are well known in the art. One skilled inthe art will recognize that the specific dosage level for any particularpatient will depend upon a variety of potentially therapeuticallyrelevant factors. For example, the dose can be determined based on thestrength of the particular antimicrobial solution employed, the severityof the condition, the body weight of the patient, the age of thepatient, the physical and mental condition of the patient, generalhealth, sex, diet, and the like. The size of the dose also can bedetermined based on the existence, nature, and extent of any adverseside effects that might accompany the administration of a particularantimicrobial solution. It is desirable, whenever possible, to keepadverse side effects to a minimum.

Factors, which can be taken into account for a specific dosage caninclude, for example, bioavailability, metabolic profile, time ofadministration, route of administration, rate of excretion, thepharmacodynamics associated with a particular HOCl water solution in aparticular patient, and the like. Other factors can include, e.g., thepotency or effectiveness of the HOCl water solution with respect to theparticular condition to be treated, the severity of the symptomspresented prior to, during or following the course of therapy, and thelike. In some instances, what constitutes a therapeutically effectiveamount also can be determined, in part, by the use of one or more of theassays, e.g., bioassays, which are reasonably clinically predictive ofthe efficacy of a particular HOCl water solution for the treatment orprevention of a particular condition.

The following examples further illustrate the invention but, of course,should not be construed as in any way limiting its scope.

Example 1

This example demonstrates a process for the preparation of theantimicrobial solution, in accordance with an embodiment of theinvention.

Process water was added to a reaction vessel. Next, sodium phosphatemonobasic monohydrate, magnesium sulfate heptahydrate, and 5N sodiumhydroxide were added. After stirring for a period of time to allow formixing, chlorine gas was bubbled through the reaction mixture. Thereaction mixture was monitored for the amount of chlorine present in thereaction mixture. Additional chlorine was added as necessary to achievethe target hypochlorous acid content. The pH of the reaction mixture wasthen adjusted by the addition of 5N sodium hydroxide to achieve a pH of3.4-5.5.

The composition of the resulting antimicrobial solution is set forth inTable 1.

TABLE 1 Component mg/L % Water n/a 99.920 Sodium 142 0.014 Magnesium 980.010 Chloride 72 0.007 Phosphate 384 0.038 Hypochlorous acid 106 0.011

Example 2

This example demonstrates the stability of the inventive antimicrobialsolution, in accordance with an embodiment of the invention.

Solutions A-F were prepared comprising about 106 mg/L of hypochlorousacid at a pH of 5.5 and having different amounts of sodiumdihydrogenphosphate and magnesium sulfate as shown in Table 2. Thesolutions were aged in glass containers at 80° C. for 130 h. The pH dropwas determined, and the results set forth in Table 2.

TABLE 2 pH Solution NaHPO₄ (grams) MgSO₄•7H₂O (grams) drop (pH units) A0.122 1.33 0.33 B 0.245 1.33 0.12 C 0.367 1.33 0.08 D 0.245 0.443 0.19 E0.245 0.887 0.16 F 0.245 1.333 0.12

As is apparent from the results set forth in Table 2, increasing theamount of sodium dihydrogenphosphate from Solution A to Solution C at aconstant level of magnesium sulfate reduced the pH drop of the solutionfrom 0.33 to 0.08. Increasing the amount of magnesium sulfate fromSolution D to Solution F at a constant level of sodiumdihydrogenphosphate reduced the pH drop of the solution from 0.19 to0.12. The small drop in pH observed for all of the solutions isindicative of the stability of the inventive antimicrobial solution.

Example 3

This example demonstrates the antimicrobial activity of the inventiveantimicrobial solution.

An antimicrobial solution prepared in accordance with an embodiment ofthe invention was tested against methicillin-resistant S. aureus (MRSA),E. coli, P. aeruginosa, Vancomycin-resistant Enterococcus, P. mirabilis,S. marcescens, and C. albicans. The log reductions at contact times of30 sec, 1 min, 2, min, 5 min, and 10 min were determined, and theresults set forth in Table 3.

TABLE 3 Contact Times (log reduction) % Bacterial Incubation Bacteria 30s 1 min 2 min 5 min 10 min reduction time (h) MRSA 8.5 8.5 8.5 8.5 8.599.9999997 24.5 E. coli 8.4 8.4 8.4 8.4 8.4 99.9999996 24 P. aeruginosa8.2 8.2 8.2 8.2 8.2 99.9999993 25 VRE 8.1 8.1 8.1 8.1 8.1 99.9999993 24P. mirabilis 8.3 8.3 8.3 8.3 8.3 99.9999995 57 S. marcescens 8.8 8.8 8.88.8 8.8 99.9999999 24.5 C. albicans 7.1 7.1 7.1 7.1 7.1 99.9999929 22.5

All references, including publications, patent applications, andpatents, cited herein are hereby incorporated by reference to the sameextent as if each reference were individually and specifically indicatedto be incorporated by reference and were set forth in its entiretyherein.

The use of the terms “a” and “an” and “the” and similar referents in thecontext of describing the invention (especially in the context of thefollowing claims) are to be construed to cover both the singular and theplural, unless otherwise indicated herein or clearly contradicted bycontext. The terms “comprising,” “having,” “including,” and “containing”are to be construed as open-ended terms (i.e., meaning “including, butnot limited to,”) unless otherwise noted. Recitation of ranges of valuesherein are merely intended to serve as a shorthand method of referringindividually to each separate value falling within the range, unlessotherwise indicated herein, and each separate value is incorporated intothe specification as if it were individually recited herein. All methodsdescribed herein can be performed in any suitable order unless otherwiseindicated herein or otherwise clearly contradicted by context. The useof any and all examples, or exemplary language (e.g., “such as”)provided herein, is intended merely to better illuminate the inventionand does not pose a limitation on the scope of the invention unlessotherwise claimed. No language in the specification should be construedas indicating any non-claimed element as essential to the practice ofthe invention.

Preferred embodiments of this invention are described herein, includingthe best mode known to the inventors for carrying out the invention.Variations of those preferred embodiments may become apparent to thoseof ordinary skill in the art upon reading the foregoing description. Theinventors expect skilled artisans to employ such variations asappropriate, and the inventors intend for the invention to be practicedotherwise than as specifically described herein. Accordingly, thisinvention includes all modifications and equivalents of the subjectmatter recited in the claims appended hereto as permitted by applicablelaw. Moreover, any combination of the above-described elements in allpossible variations thereof is encompassed by the invention unlessotherwise indicated herein or otherwise clearly contradicted by context.

The invention claimed is:
 1. An antimicrobial solution, wherein thesolution consists of: (a) about 10 mg/L to about 500 mg/L ofhypochlorous acid, (b) magnesium sulfate in an amount sufficient toprovide about 20 mg/L to about 250 mg/L of magnesium, (c) sodiumdihydrogen phosphate in an amount sufficient to provide about 200 mg/Lto about 1000 mg/L of phosphate anion formulated as PO₄ ²⁻, (d) chlorideion, and (e) water, wherein the solution has a pH of about 4.5 to about5.5.
 2. A process for the production of an antimicrobial solutioncomprising the steps of: (i) providing a mixture consisting of (a)magnesium sulfate (b) sodium dihydrogen phosphate, (c) a pH-adjustingagent, and (d) water, and (ii) adding chlorine gas to the mixture,wherein the process produces a solution consisting of hypochlorous acidin an amount from about 10 mg/L to about 500 mg/L, magnesium sulfate inan amount sufficient to provide about 20 mg/L to about 250 mg/L ofmagnesium, sodium dihydrogen phosphate is present in an amountsufficient to provide about 200 mg/L to about 1000 mg/L of phosphateanion formulated as PO₄ ²⁻, and chloride ion, and having a pH from about3 to about
 7. 3. The process of claim 2, wherein hypochlorous acid ispresent in the solution in an amount from about 50 mg/L to about 250mg/L.
 4. The process of claim 2, wherein chloride ion is present in thesolution in an amount from about 20 mg/L to about 100 mg/L.
 5. Theprocess of claim 2, wherein the chlorine gas is bubbled into themixture.
 6. A process for the production of an antimicrobial solutioncomprising the steps of: (i) providing a mixture consisting ofhypochlorous acid and water, (ii) adding (a) magnesium sulfate, (b)sodium dihydrogen phosphate, and (c) a pH-adjusting agent to themixture, and (iii) adding chloride ion to the mixture, wherein theprocess produces a solution consisting of hypochlorous acid in an amountfrom about 10 mg/L to about 500 mg/L, magnesium sulfate in an amountsufficient to provide about 20 mg/L to about 250 mg/L of magnesium,sodium dihydrogen phosphate is present in an amount sufficient toprovide about 200 mg/L to about 1000 mg/L of phosphate anion formulatedas PO₄ ²⁻, and chloride ion, and having a pH from about 3 to about
 7. 7.The process of claim 6, wherein the hypochlorous acid iselectrochemically generated.
 8. The process of claim 6, whereinhypochlorous acid is present in the solution in an amount from about 50mg/L to about 250 mg/L.
 9. The process of claim 6, wherein chloride ionis present in the solution in an amount from about 20 mg/L to about 100mg/L.
 10. A method of treating or preventing infection associated withabdominal surgery on a mammal, comprising administering to the mammal aneffective amount of the solution of claim
 1. 11. The method of claim 10,wherein the surgery is inguinal hernia surgery, exploratory laparotomy,appendectomy, or laparoscopy.
 12. The method of claim 10, wherein theinfection is caused by an organism selected from methicillin-resistantS. aureus, E. coli, P. aeruginosa, Vancomycin-resistant Enterococcus, P.mirabilis, S. marcescens, and C. albicans.
 13. The solution of claim 1,wherein chloride ion is present in the solution in an amount from about20 mg/L to about 100 mg/L.